One or more wind turbines may form a wind park which is connected to a utility grid which may provide electrical energy to plural consumers. Electrical power needed by the consumers may not in all situations balance electrical power produced by the wind turbines. In particular, if a large load is connected or switched on to the utility grid, a decrease of the frequency of the grid may be expected. In this case, the wind turbines may give only a limited inertia response, in order to support or stabilize the frequency. In other situations, the electrical power produced by the wind turbines may be larger than the power consumed by the consumers, in which case curtailment of the power from the wind turbines may be required. Thereby, in a conventional method and system, the power curtailment may be achieved by pitching out the rotor blades of the wind turbines. By pitching out the rotor blades, the efficiency of energy transfer from the wind to the rotor to which the rotor blades are connected may be decreased, resulting in a decrease of power output by the wind turbines.
The document EP 2 532 888 A1 discloses an arrangement for generating a control signal for controlling a power output of a power generation system, in particular a wind turbine, wherein a first input signal indicative of an actual grid frequency of the utility grid is received and wherein a control circuit generates a control signal and wherein the control circuit comprises a bang-bang which is activated when the first input signal falls below a first predetermined threshold. The above-mentioned document proposes a power boost function, wherein power output is increased.
It has been observed that stability of the utility grid may not be ensured in a sufficient manner in all conditions of wind speed, demand at the utility grid and operating conditions of the wind turbine.
There may be a need for a method and arrangement for controlling a wind turbine which may improve the stability of the utility grid, in particular in situations where the utility grid requires more power, in particular a sudden increase of power.